CN104821582B - Turned for optimization method and its system based on the distribution network load of nonlinear integer programming - Google Patents

Abstract

Present invention offer is a kind of to be turned for optimization method and its system based on the distribution network load of nonlinear integer programming, the distribution feeder that is mutually related in power distribution network is mapped to the multiple corresponding tree topology figure connecting by analog switch, according to the plurality of corresponding tree topology figure founding mathematical models, according to described mathematical model, calculate the variate-value of object function in described mathematical model, load transfer operation is carried out according to described variate-value；Make loss of outage minimum in the case of breaking down in power distribution network, wherein object function and constraints are all represented with clear and definite mathematic(al) representation, the non-linear integer mathematical model of formation standard, solved with general nonlinear integer programming algorithm, the variate-value solving be in power distribution network switching branches cut-off combination, thus realizing the target that under fault condition, impacted power failure range minimizes.

Description

Turned for optimization method and its system based on the distribution network load of nonlinear integer programming

Technical field

The present invention relates to power system fault analysis method field, particularly a kind of distribution based on nonlinear integer programming Net load transfer optimization method and its system.

Background technology

With China's rapid development of economy, the degree of dependence more and more higher to electric power, the development of electric power safety has been entered Enter a brand-new stages of historical development.Electrical network is the important infrastructure of relation national energy security and lifelines of the national economy And public utilities, carry is socio-economic development and national economy provides important energy safeguard, promotes economic society can hold The weighty responsibility of supervention exhibition.The reliability requirement more and more higher to supply of electric power for the modern society, the status of power industry is than ever Whenever all more important, electric power safety and be efficiently distinct issues.Distribution Network Equipment quantity is big, and species is many, bears Lotus has a very wide distribution, the complicated network structure, and running has very big uncertainty, and the generation of fault can not possibly keep away completely Exempt from it is therefore necessary to how reduce power failure in the case that fully research is broken down in power distribution network as far as possible, user power utilization to be caused The problem of loss.

When breaking down (usually short trouble), various relay protections and automaton can detect power distribution network There is abnormal change in the voltage and current of relevant device, when this change reaches the working value that various control devices are adjusted in advance When, these control devices could be made that appropriate action, on the one hand by Fault Isolation in rational scope, on the other hand due to event Barrier area of isolation presence so that those lose the path with former power supply node apart from the farther load of power ratio area of isolation, Thus also will have a power failure.By closing normally opened interconnection switch, these loads can be transferred in short-term and be associated with former feeder line Adjacent feeders, to power, shorten the time having a power failure, this is load transfer.

From the mechanism of load transfer, if can carry out to the branch road that can make opening and closing movement for a certain specific fault Optimum organization, will be carried out the minimum of impacted power failure range under fault condition.Because electrical network has transient process extremely Of short duration feature, it is desirable to the mathematical model being optimized should be as simple as possible, can be applied to common analysis skill in electrical network as far as possible Art, and more common optimized algorithm can be applied to solve.This distribution based on nonlinear integer programming proposed by the present invention Net load transfer optimization method and system have important Research Significance and engineering application value.

Content of the invention

For above-mentioned problems of the prior art, the present invention proposes a kind of power distribution network based on nonlinear integer programming Load transfer optimization method and its system, are capable of the minimum of impacted power failure range under fault condition.

A kind of being turned based on the distribution network load of nonlinear integer programming supplies optimization method, comprises the steps：

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

According to the interconnection switch connecting each bar distribution feeder, the corresponding analog switch of setting connects each tree topology described Structure chart；

Each tree topology figure founding mathematical models according to connect；

When breaking down, calculate the variate-value of described mathematical model；

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

Wherein, described mathematical model, including object function and constraints, described object function is nonlinear function,

Described object function is：

Wherein, P_i ^SPFor the injecting power of known node i, P_iIt is the injection work(with the calculated node i of computing formula Rate, P_iComputing formula be：

Wherein, V_iAnd δ_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively corresponding saving The real part of point admittance matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all branch roads all run, y_bIt is with branch admittance for diagonal entry institute structure The diagonal matrix becoming, described X is the diagonal matrix being constituted by diagonal entry 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, Road disconnects.

A kind of turned for optimization system based on the distribution network load of nonlinear integer programming, including：

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

Analog switch module, for according to the interconnection switch connecting each bar distribution feeder, the corresponding analog switch of setting is even Connect each tree topology figure described；

Mathematical model module, for each tree topology figure founding mathematical models according to connect；

Processing module, when being used for breaking down, calculates the variate-value of described mathematical model, is carried out according to described variate-value Load transfer；

Wherein, described mathematical model module includes object function submodule and constraints submodule, described object function Submodule is nonlinear function,

Described object function submodule is：

Wherein, P_i ^SPFor the injecting power of known node i, P_iIt is the injection work(with the calculated node i of computing formula Rate, P_iComputing formula be：

Wherein, V_iAnd δ_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively corresponding saving The real part of point admittance matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all branch roads all run, y_bIt is with branch admittance for diagonal entry institute structure The diagonal matrix becoming, described X is the diagonal matrix being constituted by diagonal entry 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, Road disconnects.

The present invention turns for optimization method and its system based on the distribution network load of nonlinear integer programming, by power distribution network The distribution feeder that is mutually related is mapped to the multiple corresponding tree topology figure connecting by analog switch, according to described many Individual corresponding tree topology figure founding mathematical models, according to described mathematical model, calculate target in described mathematical model The variate-value of function, carries out load transfer operation according to described variate-value；So that stopping in the case of breaking down in power distribution network Electric loss is minimum, and wherein object function and constraints are all represented with clear and definite mathematic(al) representation, forms the non-thread of standard Property integer mathematical model, solved with general nonlinear integer programming algorithm, the variate-value solving be power distribution network in switch Branch road cut-off combination, thus realizing the purpose that under fault condition, impacted power failure range minimizes.

Brief description

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

Fig. 2 be an embodiment to turn for optimization method two based on the distribution network load of nonlinear integer programming tree-shaped Topological structure connection figure；

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

Specific embodiment

In order that the object, technical solutions and advantages of the present invention are clearer, below in conjunction with accompanying drawing and specifically in fact Apply example, technical scheme is further described.

Refer to the stream turning for optimization method of an embodiment in Fig. 1 based on the distribution network load of nonlinear integer programming Cheng Tu.

A kind of being turned based on the distribution network load of nonlinear integer programming supplies optimization method, comprises the steps：

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

In one of embodiment, every distribution feeder includes at least one power end and at least one load side, different Between power end, between power end and load side and different load end by transmission line of alternation current, distribution transformer or Switchgear connects.As an independent distribution feeder, there is the load side in its independent power supply and distribution feeder, Wherein the conveying realizing electric current is connected by transmission line of alternation current, turned mutually by the height that distribution transformer can achieve voltage Change, circuit can be disconnected by switchgear, isolated fault region.

In one of embodiment, described each bar distribution feeder in power distribution network is mapped as each tree topology corresponding Structure chart, method includes：

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 is to add that on bus network branch is formed, and its transmission medium can have a plurality of branch, but 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, There is link simple, easy to maintenance it is easy to extension, the advantages of Fault Isolation is easier to, by each bar distribution feeder in power distribution network Be mapped as each tree topology figure corresponding more meet distribution feeder load side link simple, easy to maintenance it is easy to extension, Fault Isolation such as is easier at the characteristic.

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

When breaking down (usually short trouble), various relay protections and automaton can detect power distribution network There is abnormal change in the voltage and current of relevant device, when described change reaches various control devices working value set in advance When, described control device will make appropriate action, on the one hand by fault section isolation in rational scope, on the other hand by In Fault Isolation region presence so that those disconnect the company with power end apart from the power end load side more farther than fault zone Connect, thus also can have a power failure；And pass through to close normally opened interconnection switch, can be more farther than fault zone apart from power end by these Load side is transferred in the adjacent distribution feeder circuit being associated with former distribution feeder, is supplied by the power end of adjacent distribution feeder Electricity, thus realize load transfer.And according to connecting the interconnection switch of each bar distribution feeder, the corresponding analog switch of setting connects institute State each tree topology figure, load transfer relationship map is mutually connected by analog switch for each tree topology figure The relation connecing.

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

Because electrical network has transient process and its of short duration, each tree topology figure according to connect is built Vertical mathematical model, the tree topology figure that each is connected be converted into can computing mathematical model, by entering to mathematical model Row optimizes and computing, can analyze the failure problems in electrical network as quick as thought so that the power failure in the case of distribution feeder breaks down is damaged Lose minimum.

In one of embodiment, described mathematical model, including object function and constraints, described object function is non- Linear function.

In one of embodiment, described object function is：

Wherein, P_i ^SPFor the injecting power of known node i, P_iIt is the injection work(with the calculated node i of computing formula Rate, P_iComputing formula be：

Wherein, V_iAnd δ_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively corresponding saving The real part of point admittance matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all described branch roads all run, y_bIt is with branch admittance as diagonal entry The diagonal matrix being constituted, described X is the diagonal matrix being constituted by diagonal entry with membership, its expression formula For：

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, Road disconnects.

In described mathematical model, 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 exists Power flow equation should be met during steady-state operation, therefore its node imbalance power is P_i ^SP-P_i=0, that is, the computing in object function Result is zero；Power failure node is due to disconnecting with power supply node, therefore its node injecting power is P_i=0, then it is in object function Operation result be (P_i ^SP)²It can be seen that, minimum to make described object function, on the one hand should make not having a power failure number of nodes to the greatest extent May be many, the power failure power of power failure node on the other hand should be made as little as possible, the two collective effect can achieve under fault condition The purpose that impacted power failure range minimizes.

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

Described first constraints is：

I_kFor the real-time current value of k-th tree topology figure,Maximum electricity for k-th tree topology figure Flow valuve, wherein, I_kCan be calculated by following formula：

It is respectively the voltage phasor of k-th 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 ^maxIt is 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 sue for peace for 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 to break down the numbering of branch road.

It can be seen that, there is nonlinear function expression in the object function that described mathematical model includes and constraints, number The variate-value learning model is 0/1 integer value, so mathematical model is nonlinear integer programming model, has versatility, can use logical With nonlinear integer programming algorithm solve.

The object function of described mathematical model is minimised as with scope power failure influence after breaking down in distribution feeder Target, the general power that can specifically be quantified as all load buses in power supply interrupted district is minimum, is further represented as all node powers The quadratic sum of difference is minimum, and for power supply interrupted district node, its injecting power is zero, and its difference is the known load of all nodes Power, should meet power balance equation formula for non-power supply interrupted district node, that is, the known load power of non-power supply interrupted district node with The difference of its injecting power should be zero, and the node that therefore can ensure not have a power failure is as many as possible, and the power of power failure node is minimum simultaneously.

Step S104, when breaking down, calculates the variate-value of described mathematical model；

The variate-value calculating is 0/1 integer value, and " 0 " represents that branch road disconnects, and " 1 " represents branch road closure, described variate-value The vector constituting for all membership common combinations.

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, according to specific variable The connection status of the corresponding connection line of Value Operations, thus realize load transfer.

Refer to Fig. 2, turned based on the distribution network load of nonlinear integer programming for optimization method the two of an embodiment Individual tree topology connection figure, the present embodiment to describe under fault condition taking two 10kV distribution feeders connecting each other as a example The technical scheme of load transfer optimization method.

The first distribution feeder in power distribution network is mapped as corresponding tree topology Figure 24 0, wherein power end mapping For the node 200 of tree topology figure, seven load sides are each mapped to node 201, node 202, node 203, node 204th, node 205, node 206, node 207 and node 208, node 202 is connected by branch road 222 with node 205, node 205 are connected by branch road 220 with node 206, and node 205 is connected by branch road 221 with node 207, the corresponding node of power end The corresponding all nodes of the 200 pairs of load sides are powered；The second distribution feeder in power distribution network is mapped as corresponding tree topology knot Composition 250, wherein power end are mapped as the node 210 of tree topology figure, the node mapping including seven load sides, wherein One load side is mapped as node 217, and the corresponding node of power end 210 to load side, power by corresponding node 217；Described node 207 are connected by the branch road 230 that the connection line with line disconnection ability maps with node 217.

For tree topology Figure 24 0, the known burden with power vector of the node of its seven load side mappings is：

P₁ ^SP=(300 450 300 280 400 300 350 400)^TKW,

Branch resistance vector is：

R₁=(0.4 0.54 0.4 0.6 0.72 1 0.65 0.9)^TΩ,

Branch road reactance vector is：

X₁=(0.3 0.65 0.3 0.35 0.75 0.55 0.35 0.5)^TΩ；

For tree topology Figure 25 0, the known burden with power vector of the node of each load side mapping is：

Branch resistance vector is：

R₂=(0.4 0.54 0.4 0.6 0.72 1 0.65 0.9)^TΩ,

Branch road reactance vector is：

X₂=(0.3 0.65 0.3 0.35 0.75 0.55 0.35 0.5)^TΩ；

Assume that described branch road 220 is short-circuited fault, then the object function of mathematical model is：

min[(300-P_1-1)²+(450-P_1-2)²+(300-P_1-3)²+(280-P_1-4)²+(400-P_1-5)²

+(300-P_1-6)²+(350-P_1-7)²+(400-P_1-8)²+(300-P_2-1)²+(450-P_2-2)²

+(300-P_2-3)²+(280-P_2-4)²+(400-P_2-5)²+(300-P_2-6)²+(350-P_2-7)²

(400-P_1-8)²]；

Constraints is：Wherein, the first constraints is：

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：

X₂₂₀=0, represent that the variable of branch road 220 is " 0 ".

By described object function and constraints simultaneous, as the present embodiment sets the mathematics of the load transfer method of fault Model, is the nonlinear integer programming model of standard.

Try to achieve the variate-value of described mathematical model, wherein, X₂₂₀=0, X₂₂₁=0, X₂₂₂=0, X₂₃₀Remaining variable of=1, X Value is 1, represents that branch road 220, branch road 221 and branch road 222 are off-state, branch road 230 is closure state, other branch roads It is closure state.

Therefore, the load side in tree topology Figure 24 0 interior joint 205 and corresponding first distribution feeder of node 206 Have a power failure, constitute minimum power failure range, node 207 and the corresponding load side of node 217 pass through the corresponding interconnection switch of branch road 230 even Connect, the corresponding load side of node 207 is turned in the second distribution feeder being supplied to node 217 corresponding load side place, thus real The purpose that under existing fault condition, impacted power failure range minimizes.

A kind of turned for optimization system based on the distribution network load of nonlinear integer programming, including：

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

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

Mathematical model module 303, for each tree topology figure founding mathematical models according to connect；

Processing module 304, when being used for breaking down, calculates the variate-value of described mathematical model, according to described variate-value Carry out load transfer.

In one of embodiment, described mapping block includes：

Node mapping submodule, for being mapped as described tree-shaped open up the power end of described each bar distribution feeder and load side Flutter the node of structure chart；

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

In one of embodiment, described mathematical model module includes object function submodule and constraints submodule, Described object function submodule is nonlinear function.

In one of embodiment, described object function submodule is：

Wherein, P_i ^SPFor the injecting power of known node i, P_iIt is the injection work(with the calculated node i of computing formula Rate, P_iComputing formula be：

Wherein, V_iAnd δ_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively corresponding saving The real part of point admittance matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all described branch roads all run, y_bIt is with branch admittance as diagonal entry The diagonal matrix being constituted, described X is the diagonal matrix being constituted by diagonal entry with membership, its expression formula For：

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, Road disconnects.

Described constraints submodule includes the first constraints submodule, the second constraints submodule, the 3rd constraint Condition submodule and the 4th constraints submodule；Wherein,

Described first constraints submodule is：

I_kFor the real-time current value of k-th tree topology figure,Maximum electricity for k-th tree topology figure Flow valuve, wherein, I_kCan be calculated by following formula：

It is respectively the voltage phasor of k-th 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 ^maxIt is 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 sues for peace for X diagonal matrix elements, and n is node total number amount, n_sFor circuitry number Amount；

Described 4th constraints submodule is：

x_f=0, wherein, f is to break down the numbering of branch road.

The distribution based on nonlinear integer programming of present invention offer is provided by the scheme of several embodiments above Net load transfer optimization method and its system, the distribution feeder that is mutually related are mapped to are connected by analog switch in power distribution networks Multiple corresponding tree topology figure, according to the plurality of corresponding tree topology figure founding mathematical models, according to Described mathematical model, calculates the variate-value of object function in described mathematical model, carries out load transfer according to described variate-value Operation；Make loss of outage minimum in the case of breaking down in power distribution network, wherein object function and constraints are all used Clearly mathematic(al) representation, to represent, forms the non-linear integer mathematical model of standard, is calculated with general nonlinear integer programming Method solving, the variate-value solving be in power distribution network switching branches cut-off combination, thus realizing impacted under fault condition The purpose that power failure range minimizes.

Each technical characteristic of embodiment described above can arbitrarily be combined, for making description succinct, not to above-mentioned reality The all possible combination of each technical characteristic applied in example is all described, as long as however, the combination of these technical characteristics is not deposited In contradiction, all it is considered to be the scope of this specification record.

Embodiment described above only have expressed the several embodiments of the present invention, and its description is more concrete and detailed, but simultaneously Therefore the restriction to the scope of the claims of the present invention can not be interpreted as.It should be pointed out that for those of ordinary skill in the art For, without departing from the inventive concept of the premise, some deformation can also be made and improve, these broadly fall into the guarantor of the present invention Shield scope.Therefore, the protection domain of patent of the present invention should be defined by claims.

Claims (7)

1. a kind of turned for optimization method it is characterised in that comprising the steps based on the distribution network load of nonlinear integer programming：

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

According to the interconnection switch connecting each bar distribution feeder, the corresponding analog switch of setting connects each tree topology described Figure；

Each tree topology figure founding mathematical models according to connect；

When breaking down, calculate the variate-value of described mathematical model；

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

Wherein, described mathematical model, including object function and constraints, described object function is nonlinear function,

Described object 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_iIt is the injecting power with the calculated node i of computing formula, P_i Computing 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_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively respective nodes to lead Receive the real part of matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all branch roads all run, y_bConstituted with branch admittance by diagonal entry Diagonal matrix, described X is the diagonal matrix being constituted by diagonal entry 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 breaks Open.

2. according to claim 1 being turned based on the distribution network load of nonlinear integer programming supplies optimization method, and its feature exists In every distribution feeder includes at least one power end and at least one load side, between different electrical power end, power end and load Pass through transmission line of alternation current, distribution transformer or switchgear between end and between different load end to connect.

3. according to claim 1 being turned based on the distribution network load of nonlinear integer programming supplies optimization method, and its feature exists In, described each bar distribution feeder in power distribution network is mapped as each tree topology figure corresponding, method includes：

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. according to claim 1 being turned based on the distribution network load of nonlinear integer programming supplies optimization method, and its feature exists In,

Described constraints includes 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 k-th tree topology figure,For the maximum current value of k-th tree topology figure, Wherein, I_kCan be calculated by following formula：

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

It is respectively the voltage phasor of k-th tree topology figure, z_kstFor this branch impedance value；

Described second constraints is：

$V_i^{\min }\≤V_i\≤V_i^{\max },$

Wherein,WithIt is 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 sue for peace for 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 to break down the numbering of branch road.

5. a kind of turned for optimization system based on the distribution network load of nonlinear integer programming it is characterised in that including：

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

Analog switch module, for according to the interconnection switch connecting each bar distribution feeder, the corresponding analog switch of setting connects institute State each tree topology figure；

Mathematical model module, for each tree topology figure founding mathematical models according to connect；

Processing module, when being used for breaking down, calculates the variate-value of described mathematical model, carries out load according to described variate-value Turn and supply；

Wherein, described mathematical model module includes object function submodule and constraints submodule, described object function submodule Block is nonlinear function,

Described object function submodule is：

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

Wherein,For the injecting power of known node i, P_iIt is the injecting power with the calculated node i of computing formula, P_i Computing 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_iIt is respectively the amplitude of voltage and the phase angle of node i, δ_ij=δ_i-δ_j, G_ijAnd B_ijIt is respectively respective nodes to lead Receive the real part of matrix element and imaginary part, described bus admittance matrix is calculated as follows：

Y=A X y_b·X·A^T,

Wherein, A is branch road incidence matrix when all branch roads all run, y_bConstituted with branch admittance by diagonal entry Diagonal matrix, described X is the diagonal matrix being constituted by diagonal entry 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 breaks Open.

6. according to claim 5 turn for optimization system based on the distribution network load of nonlinear integer programming, its feature exists In described mapping block includes：

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

Branch road mapping submodule, for being mapped as described tree-shaped open up transmission line of alternation current, distribution transformer and switchgear Flutter the branch road of structure chart.

7. according to claim 5 turn for optimization system based on the distribution network load of nonlinear integer programming, its feature exists In,

Described constraints submodule includes 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 k-th tree topology figure,For the maximum current value of k-th tree topology figure, Wherein, I_kCan be calculated by following formula：

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

It is respectively the voltage phasor of k-th tree topology figure, z_kstFor this branch impedance value；

Described second constraints submodule is：

$V_i^{\min }\≤V_i\≤V_i^{\max },$

Wherein,WithIt is 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 sues for peace for 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 to break down the numbering of branch road.